Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967504AbaLKXAJ (ORCPT ); Thu, 11 Dec 2014 18:00:09 -0500 Received: from 251.110.2.81.in-addr.arpa ([81.2.110.251]:39070 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967198AbaLKXAG (ORCPT ); Thu, 11 Dec 2014 18:00:06 -0500 Date: Thu, 11 Dec 2014 22:57:18 +0000 From: One Thousand Gnomes To: Bjorn Helgaas Cc: Jesse Barnes , Greg Kroah-Hartman , Dely Sy , "linux-pci@vger.kernel.org" , Rajat Jain , Guenter Roeck , Kristen Carlson Accardi , "linux-kernel@vger.kernel.org" , Praveen Kalamegham Subject: Re: Special handling of display/VGA devices in hotplug drivers Message-ID: <20141211225718.403ada7e@lxorguk.ukuu.org.uk> In-Reply-To: References: <20141211181136.GA11367@kroah.com> <20141211113243.3f21551e@jbarnes-t420> Organization: Intel Corporation X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.24; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > >> The PCI spec said that you were not allowed to hotplug VGA drivers. > >> The big issue is that POST usually needs to run on those things, and > >> there is no way to POST a PCI hotplugged device. > > I don't think this is a problem any more, is it? I think X can > execute option ROMs, and if we assign the guest to a VM, the guest > BIOS can also do it. Providing the legacy I/O is routed to that device, it doesn't use DMA and a few other things. X has been able to POST cards with vm86 or the 8086 emulator stuff for a long time (it had to in order to use most PC cards on non x86 boxes). Your bigger problem is the marvellous reliable way that X handles a GPU simply vanishing, especially a legacy one. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/